The present invention relates to a membrane separation device and method of manufacturing said device. The membrane separation device comprises a housing or case within which is fixedly situated a membrane separation module fabricated from a plurality of semi-permeable hollow fiber membranes.
Separatory devices containing a hollow fiber membrane separation module useful for dialysis, microfiltration, ultrafiltration, reverse osmosis, blood oxygenation, gas separation, pervaporation, membrane stripping, and the like, are well known. Various methods of manufacture have been described. In general, however, the hollow fiber separation module consists of a plurality of fine hollow fibers whose end portions are potted in one or two active tubesheet(s) and whose open-fiber ends terminate in one or two active tubesheet face(s) which provides an access for fluid to enter or exit the interior of the hollow fibers, thereby forming a module comprising a bundle of hollow fibers and one or two tubesheets. The hollow fiber module is sealed in a housing or case in such a manner that two regions are defined by fluid flow which is controlled by the separatory or permeation properties of the hollow fiber membranes. The two regions are generally designated as the shellside and the tubeside. The shellside region is that region exterior to the hollow fibers which is between the tubesheets, while the tubeside region is that region on the interior of the hollow fibers. Each region may have fluid flowing through it, of higher or lower pressure than the other, depending on whether the feed fluid into the device is on the exterior or the interior of the hollow fibers. The driving force for transport through or across the hollow fibers may be due to a difference in pressure, concentration, and/or electrical potential.
The hollow fiber separation module may have one or two active tubesheets: in the former case the hollow fibers are doubled back so that all the ends of the hollow fibers terminate together in the one active tubesheet. A hollow fiber separation module possessing one such active tubesheet in which all hollow fiber ends terminate may also possess a non-active tubesheet to facilitate formation of the hollow fiber bundle and sealing the hollow fiber bundle within the housing or case. A non-active tubesheet does not contain the terminal ends of the hollow fibers. That is, fluid can not be introduced into or withdrawn from such a non-active tubesheet. The tubesheet(s) binds the hollow fibers together and holds them in place. Each tubesheet is also sealed to the inner wall surfaces of the housing or case, thus fixing the separatory module in place within the case. The tubesheet(s) together with the case define the shellside region external to the hollow fibers which does not communicate directly with the interior lumens of the hollow fibers.
Patents representative of the art of hollow fiber membrane separation devices include U.S. Pat. Nos. 2,972,349; 3,328,876; 3,228,877; 3,422,008; 3,423,491; 3,339,341; 3,403,515; and the like.